Sir George Paget Thomson (1892-1975) was British physicist who won the 1937 Nobel Prize for his experimental discovery of the diffraction of electrons by crystals. This glass slide—an electron diffraction image of platinum magnetic deflrection, taken by Thomson and his student Alexander Reid—is a copy, made at the Smithsonian, of an original borrowed from Thomson, for an exhibit on “35 Years With Electrons As Waves.”
Ref: George Paget Thomson, “Early Work in Election Diffraction,” American Journal of Physics 29 (1961): 1-15.